Biaxial stretching and blow molding device

ABSTRACT

A biaxial stretch blow molding device comprises: a first guide shaft which is erected on an upper base and to which a blow core fixing member is slidably coupled; a second guide shaft erected on the stretch rod fixing member; a support member fixed to the first guide shaft and provided with a guide hole through which the second guide shaft is slidably inserted; a first drive device that moves the blow core fixing member forward and backward independently of the stretch rod fixing member; and a second drive device that moves the stretch rod fixing member forward and backward independently of the blow core fixing member.

This application is a continuation of U.S. application Ser. No.15/706,542, filed Sep. 15, 2017, which is a continuation of PCTInternational Application No. PCT/JP2016/058319, filed on Mar. 16, 2016,which claims priority under 35 U.S.C. 119(a) to Patent Application No.2015-055264, filed in Japan on Mar. 18, 2015, all of which are herebyexpressly incorporated by reference into the present application.

TECHNICAL FIELD

This invention relates to a biaxial stretch blow molding device whichblow-molds a preform while stretching it by a stretch rod to form ahollow container.

BACKGROUND ART

Biaxial stretch blow molding devices have so far been known as devicesfor producing hollow containers made of synthetic resins, such asplastic containers. In the biaxial stretch blow molding device, it iscommon practice that a preform is transported to a blow mold by arotating disk, with a neck of the preform being held; the preform isstretched by a stretch rod within the blow mold; and high pressure airis fed into the preform via a blow core mold for closing a mouth(opening) of the preform, whereby a hollow container is blow-molded. Inthis manner, a hollow container of a desired shape can be formed.

The biaxial stretch blow molding device is configured, for example, asfollows: A core fixing plate to which a blow core mold is fixed israised or lowered (moved forward or backward), together with anelevation block, by a first air cylinder provided in a fixed block. Anelevation plate to which a stretch rod is fixed is raised or lowered bya second air cylinder provided in the elevation block (see, for example,Patent Document 1).

In forming a hollow container by such a biaxial stretch blow moldingdevice, the stretch rod is moved (lowered) by the second air cylinder,with the movement (e.g., descent) of the blow core mold being stopped.Since air is compressed or expanded, it is difficult to exercise finecontrol of speed simply by the air cylinder. Thus, if it is attempted tooperate the first air cylinder and the second air cylinder synchronouslyin the device described in Patent Document 1, for example, deviationbetween their timings may exert an influence to induce damage to thedevice.

Generally, in order that the stretch rod has been inserted to a sitenear the bottom of the preform at the completion of the movement(descent) of the blow core mold, the stretch rod is lowered beforehandto a predetermined position conformed to the length of the preform, at astandby (ascent) position before descent of the blow core mold. That is,at the standby position, the stretch rod is protruded with apredetermined length below the blow core mold. By so doing, a cycle timetaken for blow molding can be shortened.

In this case, however, in order to avoid interference between thestretch rod and the rotating disk for transporting the preform, there isneed to set a position upwardly apart from the rotating disk by anamount, which is equal to or more than the amount of protrusion of thestretch rod from the blow core mold, as the standby position of the blowcore mold.

To close the neck mold for the preform with the blow core mold,therefore, it is necessary to lower the blow core mold by at least adistance corresponding to the amount of protrusion of the stretch rod.That is, the stroke amount of the blow core mold during ascent ordescent becomes relatively large. As a result, the problem occurs thatthe time taken for ascent or descent of the blow core mold lengthens,resulting in a long cycle time taken by blow molding.

To deal with such a problem, a device is available in which a drivesource for the blow core mold or the stretch rod is changed from apneumatic cylinder to a servo motor to achieve a reduction in the cycletime. A concrete example is a device which is equipped with a firstservo motor and a second servo motor, and in which when the second servomotor is stopped, the first servo motor is driven to move a blow corefixing plate and a stretch rod fixing plate forward or backward; or whenthe first servo motor is stopped, the second servo motor is driven tomove the stretch rod fixing plate forward or backward independently(see, for example, Patent Document 2).

By moving the blow core mold and the elevation rod forward or backward(upward or downward), as described above, the time taken for the ascentor descent of the blow core mold and the elevation rod shortens, and canthus reduce the cycle time.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP-A-Hei-6-254955

Patent Document 2: Japanese Patent No. 3391904

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Even in the device described in Patent Document 2, however, the stretchrod basically needs to be moved (lowered), with the blow core mold beingstopped. This poses the problem, as in the device described in PatentDocument 1, that the stroke amount of the blow core mold during ascentor descent is large, and the cycle time cannot be sufficientlyshortened. Since the first servo motor and the second servo motor arefixed on the same member, moreover, vibrations associated with theascent or descent of the blow core mold may be transmitted to the motorfor driving the stretch rod, causing communication abnormalities. In thebiaxial stretch blow molding device operated at a high speed, inparticular, if the motion of the stretch rod delays because of acommunication abnormality, there is a possibility that the stretch rodwill interfere with a movable member including the rotating disk. Theinfluence of such an abnormality is not negligible.

The present invention has been accomplished in the light of theabove-described circumstances. It is an object of the invention toprovide a biaxial stretch blow molding device which can efficiently movea blow core mold and a stretch rod forward or backward to shorten thecycle time and stabilize a molding action.

Means for Solving the Problems

A first aspect of the present invention, which solves the aboveproblems, resides in a biaxial stretch blow molding device for driving ablow core fixing member to which a blow core mold is fixed, and astretch rod fixing member to which a stretch rod is fixed, to moveforward and backward, comprising: a first guide shaft which is erectedon an upper base and to which the blow core fixing member is slidablycoupled; a second guide shaft erected on the stretch rod fixing member;a support member fixed to the first guide shaft and provided with aguide hole through which the second guide shaft is slidably inserted; afirst drive device that moves the blow core fixing member forward andbackward independently of the stretch rod fixing member; and a seconddrive device that moves the stretch rod fixing member forward andbackward independently of the blow core fixing member.

A second aspect of the present invention resides in the biaxial stretchblow molding device according to the first aspect, wherein the seconddrive device includes a servo motor, and the servo motor is fixed to thesupport member.

A third aspect of the present invention resides in the biaxial stretchblow molding device according to the second aspect, wherein the seconddrive device includes a slide shaft linearly moved in an axial directionby rotation of the servo motor, and one end side of the slide shaft isconnected to the stretch rod fixing member.

A fourth aspect of the present invention resides in the biaxial stretchblow molding device according to any one of the first to third aspects,wherein the first drive device includes an air cylinder, and the aircylinder is fixed to the upper base.

A fifth aspect of the present invention resides in the biaxial stretchblow molding device according to any one of the first to fourth aspects,wherein the stretch rod fixing member is disposed to contact the blowcore fixing member when the stretch rod fixing member is driven to movebackward.

Effects of the Invention

According to the biaxial stretch blow molding device of the presentinvention, the blow core fixing member to which the blow core mold isfixed, and the stretch rod fixing member to which the stretch rod isfixed can be driven to move forward and backward independently. Thus,the blow core fixing member and the stretch rod fixing member can bedriven to advance and retreat efficiently at the same timing.Consequently, the time taken for the movement (forward or backwardmovement) of the blow core fixing member and the stretch rod fixingmember can be shortened and, eventually, the cycle time taken for blowmolding can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the configuration of an injectionblow molding device according to an embodiment of the present invention.

FIG. 2 is a front view showing essential parts of a biaxial stretch blowmolding device according to the embodiment of the present invention.

FIG. 3 is a side view showing the essential parts of the biaxial stretchblow molding device according to the embodiment of the presentinvention.

FIGS. 4A to 4C are views illustrating the actions of the biaxial stretchblow molding device according to the embodiment of the presentinvention.

FIGS. 5A to 5C are views illustrating the actions of the biaxial stretchblow molding device according to the embodiment of the presentinvention.

MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will now be described in detailby reference to the accompanying drawings.

First of all, an explanation will be offered for the schematicconfiguration of an injection blow molding apparatus equipped with abiaxial stretch blow molding device.

As shown in FIG. 1, an injection blow molding apparatus 1 according tothe present embodiment is a so-called one-stage injection blow moldingapparatus for producing, for example, a hollow container made of asynthetic resin, such as a bottle for a beverage. An injection moldingdevice (injection molding station) 3, a temperature control device(temperature control station) 4, a biaxial stretch blow molding device(blow molding station) 5, and a withdrawal device (withdrawal station) 6are provided on a machine base 2 of the injection blow molding apparatus1.

A nozzle 7 of an injection device is coupled to the injection moldingdevice 3, and a preform is injection-molded in the injection moldingdevice 3. In the temperature control device 4, the temperature of thepreform is adjusted to a desired temperature. In the biaxial stretchblow molding device 5, the temperature-adjusted preform is biaxiallystretched and blow-molded to form a hollow container which is a finalmolded product. The so formed hollow container is withdrawn to theoutside by the withdrawal device 6.

A rotating disk 8 is provided above the injection molding device 3, thetemperature control device 4, the biaxial stretch blow molding device 5,and the withdrawal device 6. The rotating disk 8 is, for example,intermittently rotatable counterclockwise with respect to the machinebase 2. Lip molds 9 are provided at four locations in thecircumferential direction of the rotating disk 8. With their necks beingheld by the lip molds 9, the preform and the hollow container aretransported to the predetermined devices sequentially by theintermittent rotation of the rotating disk 8.

The present invention is characterized by the configuration of thebiaxial stretch blow molding device 5 constituting the above-describedinjection blow molding apparatus 1. Hereinafter, a detailed descriptionwill be presented of the configuration of the biaxial stretch blowmolding device 5, particularly, a drive mechanism unit for driving ablow core fixing plate, to which a blow core mold for closing a mouth(opening) of the preform is fixed, and a stretch rod fixing plate, towhich a stretch rod is fixed, to advance and retreat (ascend anddescend) with respect to a blow cavity mold. FIG. 2 is a front viewshowing essential parts of the biaxial stretch blow molding device 5,particularly, the configuration of the drive mechanism unit. FIG. 3 is aside view of the drive mechanism unit.

As shown in FIGS. 2 and 3, the biaxial stretch blow molding device 5 hasa blow cavity mold 52 below an upper base 51. Since the blow cavity mold52 is of an existing configuration, its detailed explanation andillustration will be omitted. Briefly, the blow cavity mold 52 includesa pair of split molds and, at a position thereof corresponding to eachlip mold 9, is formed with a molding space (cavity) conformed to theshape of the hollow container as the final molded product.

A blow core fixing plate (blow core fixing member) 54 to which a blowcore mold 53 is fixed, and a stretch rod fixing plate (stretch rodfixing member) 56 to which a stretch rod 55 is fixed are provided abovethe upper base 51 of the biaxial stretch blow molding device 5. A drivemechanism unit 100 is further provided for moving the blow core fixingplate 54 and the stretch rod fixing plate 56 forward and backward. Theterm “moving forward and backward” or a similar term means moving theblow core fixing plate 54 and the stretch rod fixing plate 56 to advancetoward the blow cavity mold 52, and moving them to retreat away from theblow cavity mold 52.

To the blow core fixing plate 54, the respective blow core molds 53 arefixed at positions corresponding to the plurality of lip molds 9. Theblow core fixing plate 54 can be moved forward and backward with respectto the blow cavity mold 52 and, in the present embodiment, are movableupward and downward (ascendable and descendable), by the drive mechanismunit 100.

Concretely, on the upper base 51, a pair of first guide shafts 57 iserected on each of both sides, with the blow core fixing plate 54 beinglocated therebetween. That is, two of the first guide shafts 57 arearranged in parallel on each side of the blow core fixing plate 54, sothat a total of the four first guide shafts 57 are erected on the upperbase 51. A plate-shaped reinforcing frame 58 is provided behind thefirst guide shaft 57 (on the right side in FIG. 3). A support member 59is fixed to the distal ends (upper ends) of the four first guide shafts57 and the reinforcing frame 58.

Side plates 60 are provided at both ends of the blow core fixing plate54. These side plates 60 are each provided opposite the two first guideshafts 57 arranged in parallel, and their lower ends are fixed to theblow core fixing plate 54. The upper ends of the side plates 60 arecoupled together by a coupling plate 61 disposed in parallel to the blowcore fixing plate 54. A slide member 62 mounted slidably on the opposingtwo first guide shafts 57 is fixed to each side plate 60. That is, theblow core fixing plate 54 is coupled slidably to the first guide shafts57 via the side plates 60 and the slide members 62.

Air cylinders 63, as a first drive device that moves the blow corefixing plate 54 forward and backward, are provided outwardly of the pairof first guide shafts 57. That is, the blow core fixing plate 54 ismovable by the two air cylinders 63. These air cylinders 63 are eachcomposed of a cylinder portion 64 fixed to the upper base 51, and adrive rod 65 to be driven vertically by the cylinder portion 64. Thedistal end of the drive rod 65 is coupled to a lower surface of anextension member 66 extended from the slide member 62 to a positionopposing the drive rod 65. In this manner, the air cylinder 63 iscoupled to the blow core fixing plate 54 via the extension member 66,the slide member 62, and the side plate 60.

With the foregoing configuration of the drive mechanism unit 100, theair cylinder 63 is driven to move the drive rod 65 upward (i.e. advanceit) by a rise in the air pressure within the cylinder portion 64. Inaccordance with this movement, the extension member 66 is pressedupward, and the blow core fixing plate 54 is moved upward along thefirst guide shafts 57 together with the extension member 66. When theair cylinder 63 is driven to move the drive rod 65 downward (i.e.,retreat it), by contrast, the blow core fixing plate 54 is moveddownward together with the extension member 66.

On the other hand, a plurality of the stretch rods 55 corresponding tothe plurality of blow core molds 53 each have one end (upper end) fixedto the stretch rod fixing plate 56. The other end (lower end) side ofeach stretch rod is inserted into the blow core mold 53 via athrough-hole (not shown) formed in the blow core fixing plate 54. Thestretch rod fixing plate 56 is disposed below the aforementionedcoupling plate 61 and, like the blow core fixing plate 54, is configuredto be movable forward and backward with respect to the blow cavity mold52 and, in the present embodiment, be movable upward and downward(ascendable and descendable), by the drive mechanism unit 100.

Concretely, on a surface of the stretch rod fixing plate 56 on a sideopposite to the stretch rods 55 (i.e., upper surface of the stretch rodfixing plate 56), second guide shafts 67 are erected near both ends ofthe surface. These paired second guide shafts 67 are extended upwardlyof the support member 59. The coupling plate 61 disposed above thestretch rod fixing plate 56 is formed with a first opening (not shown)of such a size that the second guide shaft 67 does not contact the firstopening. The support member 59 is provided with guide holes 68 throughwhich the second guide shafts 67 are inserted slidably to guide themovement of the second guide shafts 67. In the present embodiment, theguide hole 68 is constituted by a cylindrical guide hole formationmember 69 of a length larger than the thickness of the support member59, and this guide hole formation member 69 is attached to the supportmember 59.

The guide hole formation member 69 is attached to the support member 59so as to protrude downwardly of the support member 59 by a predeterminedamount. When the blow core fixing plate 54 is raised, the coupling plate61 contacts the guide hole formation member 69, thereby restraining theascent of the blow core fixing plate 54. That is, in the presentembodiment, the upper limit position (standby position) of the blow corefixing plate 54 is determined by the guide hole formation member 69.

Needless to say, the configuration for determining the upper limitposition of the blow core fixing plate 54 is not particularly limited. Astopper member for restraining the upward movement of the blow corefixing plate 54 may be provided separately from the guide hole formationmember 69. This stopper member may be provided, for example, in a partof the upper surface of the coupling plate 61 which the second guideshaft 67 does not penetrate, or may be provided on the lower surface ofthe support member 59.

A servo motor 70 constituting a second drive device that moves theabove-mentioned stretch rod fixing plate 56 to advance or retreat isfixed onto the support member 59. A drive gear 71 is fixed to a rotatingshaft of the servo motor 70, and a stretch rack (slide shaft) 73 havingon one surface side thereof a gear portion 72 to be meshed with thedrive gear 71 is provided in a predetermined length on the stretch rodfixing plate 56. The coupling plate 61 and the support member 59disposed above the stretch rod fixing plate 56 are each formed with asecond opening (not shown) of such a size that the stretch rack 73 doesnot contact the second opening.

In the foregoing configuration of the drive mechanism unit 100, when theservo motor 70 is driven to rotate the drive gear 71 in mesh with thegear portion 72 of the stretch rack 73 in one direction(counterclockwise in FIG. 2), the stretch rack 73 is moved upward inaccordance with this rotation. That is, the stretch rod fixing plate 56to which the stretch rack 73 is fixed is moved upward along the secondguide shafts 67. When the servo motor 70 is driven to rotate the drivegear 71 in the other direction (clockwise in FIG. 2), by contrast, thestretch rod fixing plate 56 is moved downward along the second guideshafts 67 in accordance with this rotation.

According to the biaxial stretch blow molding device 5 equipped with thedrive mechanism unit 100 of the above configuration, the blow corefixing plate 54 and the stretch rod fixing plate 56 can be moved forwardand backward efficiently, and the cycle time taken for blow molding canbe shortened.

Next, an example of the actions of the blow core fixing plate 54 and thestretch rod fixing plate 56 will be described by reference to FIGS. 4Ato 4C and FIGS. 5A to 5C.

When a preform 200 is transported to the blow cavity mold 52 of thebiaxial stretch blow molding device 5, as shown in FIG. 4A, the blowcore fixing plate 54 is raised by the air cylinder 63, whereby the blowcore mold 53 is held at a position where it does not interfere with therotating disk 8. In the present embodiment, the blow core fixing plate54 is held at the standby position where the coupling plate 61 contactsthe guide hole formation member 69. At this time, the stretch rod 55 hasits distal end (lower end) held in such a state as to be on a par with,or slightly protrude from, the lower end of the blow core mold 53. Inother words, the stretch rod 55 is held in such a state that its distalend (lower end) scarcely protrudes from the lower end of the blow coremold 53. Thus, with the blow core fixing plate 54 being located at thestandby position, the blow core mold 53 is disposed at a positionrelatively close to the blow cavity mold 53 (preform 200).

Then, as shown in FIG. 4B, the air cylinder 63 is driven to move thedrive rod 65 downward (retreat it). As a result, the blow core fixingplate 54 descends along the first guide shafts 57. The blow core fixingplate 54 lowers each blow core mold 53 to a position where the blow coremold 53 seals the mouth of the preform 200.

At the same timing as that for lowering the blow core fixing plate 54,the servo motor 70 is driven to rotate the drive gear 71 in apredetermined direction (clockwise in FIG. 4B, 4C). By so doing, thestretch rod fixing plate 56 descends together with the stretch rack 73.The stretch rod fixing plate 56 is lowered to a position where thedistal end of the stretch rod 55 comes close to the bottom of thepreform 200.

For convenience of explanation, FIG. 4B shows a state in which the blowcore fixing plate 54 is lowered, and FIG. 4C shows a state in which thestretch rod fixing plate 56 is further lowered. Actually, however, theblow core fixing plate 54 and the stretch rod fixing plate 56 arelowered at the same timing, as mentioned above. That is, during thedescent of the blow core fixing plate 54, the stretch rod fixing plate56 is also lowered.

In the present embodiment, as described above, the air cylinder 63 asthe first drive device that moves the blow core fixing plate 54 forwardand backward is fixed to the upper base 51, whereas the servo motor 70constituting the second drive device that moves the stretch rod fixingplate 56 forward and backward is fixed to the support member 59. Thatis, the air cylinder 63 and the servo motor 70 are fixed independentlyof each other, and one of them does not affect the action of the other.Hence, the air cylinder 63 and the servo motor 70 can be operated at thesame timing. Moreover, an encoder and wiring of the servo motor 70 areconfigured not to undergo vibrations or impulses associated with theascent or descent motion of the blow core fixing plate 54, andassociated communication abnormalities are also inhibited fromoccurring. Consequently, the synchronous operation of the biaxialstretch blow molding device 5, for example, the synchronous operation ofthe rotating disk 8 and the stretch rod fixing plate 56, can be carriedout more reliably, thus enhancing the stability of mechanical actions(molding actions) during blow molding.

The “same timing” means that there is a period of time during which thestretch rod fixing plate 56 and the blow core fixing plate 54 movesimultaneously, and the servo motor 70 and the air cylinder 63 need notnecessarily be started at the same time. The timing for starting theservo motor 70 and the air cylinder 63 may be determined, asappropriate, in consideration of the ascent speeds of the stretch rodfixing plate 56 and the blow core fixing plate 54, respectively, so thatthe descent of the stretch rod fixing plate 56 ends during the descentof the blow core fixing plate 54.

As shown in FIG. 5A, the servo motor 70 is driven to rotate the drivegear 71 in a predetermined direction (clockwise in FIG. 5A) to furtherlower the stretch rod 55. At the same time, high pressure air issupplied into the preform 200 via the blow core mold 53 to blow-mold thepreform 200, thereby forming a hollow container 210 of a predeterminedshape.

Then, as shown in FIG. 5B, the servo motor 70 is driven to rotate thedrive gear 71 in a predetermined direction (counterclockwise in thedrawing) to raise the stretch rod fixing plate 56. At practically thesame timing as that for the ascent of the stretch rod fixing plate 56,the air cylinder 63 is driven to raise the blow core fixing plate 54.The timing for raising the blow core fixing plate 54 is preferably atleast before contact of the stretch rod fixing plate 56 with thecoupling plate 61, more preferably simultaneous with the ascent of thestretch rod fixing plate 56.

According to the above procedure, until the stretch rod fixing plate 56contacts the coupling plate 61, the stretch rod fixing plate 56 and theblow core fixing plate 54 ascend independently of each other. After thestretch rod fixing plate 56 contacts the coupling plate 61, the stretchrod fixing plate 56 and the blow core fixing plate 54 ascend insynchronization, as shown in FIG. 5C. On this occasion, the blow corefixing plate 54 is pushed up even by the stretch rod fixing plate 56,that is, the blow core fixing plate 54 is raised by the driving force ofthe servo motor 70 as well as the air cylinder 63. Thus, the blow corefixing plate 54 and the stretch rod fixing plate 56 can be raised to thestandby position at an earlier stage.

Under certain molding conditions such as the production of awide-mouthed container, the blow core mold 53 may be tightly fitted tothe neck of the preform 200, and the ascent motion of the blow core mold53 may be delayed by the action of the air cylinder alone. In such acase, the biaxial stretch blow molding device 5 according to the presentinvention can suppress a delay in the motion of the blow core mold 53 byassisting the ascending motion of the blow core fixing plate 54 by theforce of the servo motor 70 via the stretch rod fixing plate 56.

When the blow core fixing plate 54 and the stretch rod fixing plate 56ascend to the standby position, the air cylinder 63 and the servo motor70 are stopped, whereby the motions of the blow core fixing plate 54 andthe stretch rod fixing plate 56 during blow molding (one cycle) arecompleted.

With the biaxial stretch blow molding device 5 according to the presentinvention, as described above, the stretch rod fixing plate 56 can alsobe lowered independently during the descent of the blow core fixingplate 54. Thus, the stretch rod 55 need not be protruded, at the standbyposition, from the blow core mold 53 in conformity with the length ofthe preform. Hence, the distance between the blow core mold 53 and thepreform at the standby position can be rendered relatively short, andthe stroke amount of the blow core mold 53 can be kept small.Accordingly, the time required for lowering the blow core mold 53 isshort, and the cycle time is shortened.

Furthermore, when the blow core fixing plate 54 is raised, the power ofthe servo motor 70 as well as the air cylinder 63 is utilized. Thus, thenecessary time for raising the blow core fixing plate 54 and the stretchrod fixing plate 56 to the standby position is also shortened. Hence,the cycle time taken for blow molding can be shortened further.

The one embodiment of the present invention has been described as above,but it is to be understood that the present invention is in no waylimited to this embodiment. The present invention can be changed ormodified, as appropriate, without departing from its spirit and scope.

EXPLANATIONS OF LETTERS OR NUMERALS

1 Injection blow molding apparatus

2 Machine base

3 Injection molding device

4 Temperature control device

5 Biaxial stretch blow molding device

6 Withdrawal device

7 Nozzle

8 Rotating disk

9 Lip mold

51 Upper base

52 Blow cavity mold

53 Blow core mold

54 Blow core fixing plate

55 Stretch rod

56 Stretch rod fixing plate

57 First guide shaft

58 Reinforcing frame

59 Support member

60 Side plate

61 Coupling plate

62 Slide member

63 Air cylinder

64 Cylinder portion

65 Drive rod

66 Extension member

67 Second guide shaft

68 Guide hole

69 Guide hole formation member

70 Servo motor

71 Drive gear

72 Gear portion

73 Stretch rack

100 Drive mechanism unit

200 Preform

210 Hollow container

The invention claimed is:
 1. A biaxial stretch blow molding device fordriving a blow core fixing member to which a blow core mold is fixed,and a stretch rod fixing member to which a stretch rod is fixed, to moveforward and backward, the biaxial stretch blow molding devicecomprising: a first guide shaft to which the blow core fixing member isslidably coupled; a second guide shaft erected on the stretch rod fixingmember; a support member fixed to the first guide shaft and providedwith a guide hole through which the second guide shaft is slidablyinserted; a first drive device that moves the blow core fixing memberforward and backward independently of the stretch rod fixing member; asecond drive device that moves the stretch rod fixing member forward andbackward independently of the blow core fixing member; side platesprovided to two ends of the blow core fixing member; and slide membersslidably mounted to the first guide shaft, the respective slide membersbeing fixed to the respective side plates, wherein the blow core fixingmember is slidably coupled to the first guide shaft via the slide platesand the slide members.
 2. The biaxial stretch blow molding deviceaccording to claim 1, further comprising a coupling plate disposed inparallel to the blow core fixing member, wherein upper ends of the sideplates are connected each other via the coupling plate.
 3. The biaxialstretch blow molding device according to claim 1, wherein the seconddrive device includes: a servo motor; and a slide shaft linearly movablein an axial direction by rotation of the servo motor, and wherein oneend side of the slide shaft is connected to the stretch rod fixingmember.
 4. The biaxial stretch blow molding device according to claim 1,wherein the stretch rod fixing member is disposed to contact the blowcore fixing member when the stretch rod fixing member is driven to movebackward.